Hydrodynamic bullet catcher



Nov. 19, 1957 K. E. scHuEssLER HYDRODYNAMIC BULLET CATCHER 2 Sheets-Sheet 1 Filed qu@ 24, 1955 INVENTOR.

KARLy E. SCHUESSLER ,fm Ma ATTORNEYS U m. m N .Sm

S S. mv mm En F12 2b Nov. 19, 1957 K. E. scHuEssLl-:R 2,813,422

, HYDRODYNAMIG BULLET CATCHER Filed June 24, 1955 2 Sheets-Sheet 2 19h` 28 27e 19a 22 INVENTOR.

KARL E. SCHUESSLER mml.

ATTORNEYS Unite States Patent() HYDRODYNAMIC BULLET CATCHER Karl E. Schuessler, Philadelphia, Pa., assgnor to the United States of America as represented by the Secretary of the Navy Application June 24, 1955, Serial No. 517,951 Claims. (Cl. 73-167) (Granted under Title 35, U. S. Code (1952), sec. 266) A conventional apparatus for trapping projectiles tired i.

from firearms undergoing testing involves the use of a bank of sand to form a stop for the projectiles. This conventional method has several disadvantages. The projectiles trapped in the sand accumulate, especially during a round of rapid tiring, forming masses of metal which may deflect subsequently fired projectiles causing a hazard to personnel and equipment. As a result, it becomes necessary at frequent intervals to perform the laborious and time-consuming operation of cleaning out the sand which, of course, is not feasible during a prolonged period of ring. Moreover, the repeated impacts of projectiles striking the sand pulverize it to such an extent `that it must frequently be altogether replaced.

. `The use of water in bullet trapping devices has been y suggested before. However, al1 such proposed devices have had several important defects which this invention overcomes. One disadvantage of previous equipment designed for the use of water is the large size and extreme bulkiness of the apparatus required. A second disadvantage is the large quantity of water which must be used.

Also entering this tube from an annular entrance surrounding the path of the bullets is a convergent How of water under pressure and at high velocity. The bullets make initial contact with the water at or near the apex of the conical water surface formed by the convergent water ow causing an immediate destabilization of the bullets so that a substantially shorter column of uid is fully elfective to decelerate them. The projectiles become entrained in the column of water within the tube and they are slowed down to substantially the rate of flow of the water. The water and the entrained projectiles are then reversed in direction at the end of the length of the tube by a specially designed deflector to pass through an annular space between the tube and an outer casing. Thisreverse flow returns the water to a tank for reuse whilethe projectiles, due to their weight, drop into a trap provided for this purpose. The decelerating tube and deflector are specially mounted to absorb shock and eliminate noise and vibration.

It is thus an object of the present invention to provide a--hydrodynamic bullet-catcherr which is compactand frice highly effective` for trapping projectiles tired. at a rapid rate.

It is another object to provide a bullet catcher utilizing a column of water to trap a plurality of projectiles sequentially fired and carry away these projectiles at a rapid rate, thereby preventing a tired projectile from being deflected by a previously fired projectile.

A further object of the invention is the provision of a device for maintaining a solid column of water traveling at a high rate of speed suitable for carrying away quickly, effectively and efficiently a plurality of sequentially delivered projectiles.

Still another object of this invention is to provide apparatus for absorbing the shock and energy of a rapidly moving object byutilizing a conically shaped water surface for initially destabilizing the approaching object.

Another object of the present invention is the provision of a closed system bullet catcher which is compact and safe using water as the medium.

Other objects and features of the invention will become more apparent to those skilled in the art as the disclosure is made in the following detailed description of a preferred embodiment of the invention as illustrated in the accompanying sheets of drawing in which:

Fig. 1 shows a side View, partly in section, of a preferred embodiment of the invention; f

Fig. 2 shows a detail of the front end of the catcher assembly;

Fig. 3 shows a section 3-3 of the bullet trap of Fig. 1

Fig. 4 illustrates how an approaching projectile is destabilized by this invention; and

Fig. 5 is a section 5-5 from Fig. 3 showing details omitted from Fig. l.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in Fig. l a gun 6 with a barrel 6a mounted for test firing into the bullet catcher of this invention. The bullet catcher consists generally of a water pump 7, a water tank 8, and a bullet catcher assembly 9. Motor driven pump 7 supplies water under pressure from tank 8 to catcher assembly 9 through conduit 11. The water returns to tank 3, which may be pressurized, via conduit 13. Conduit 14 is for the purpose of supplying or withdrawing water from the system and conduit 12 is a drain for chamber 15. Catcher assembly 9 comprises two cylindrical casings 16 and 17 which are joined at 18 and are displaced axially from each other forming a shoulder 18a, as illustrated, for the purpose explained below. Casing 16 has an end plate 19 with an opening 21 therein for permitting passage of the projectiles into bullet catcher assembly 9. Within casing 16 is provided a water director 22 of which there is a simplified representation in Fig. 1 and a more detailed showing in Fig. 2. Director 22 forms an annular orice 23 with a ring 24 also mounted within casing 16. Chamber 10 is the space outside deector 22 and between plate 19 and ring 24. `Annular orice 23 is made adjustable by the arrangement shown in detail in Fig. 2. End plate 19 is provided with a cylindrical extension 19a forming a part of water director 22. An inner sleeve 26 rigid with extension 19a is provided with a plurality of tapped holes 26a arranged circularly about the axis of director 22. A movable element 27 has a conical end 27a which forms the annular orice 23 with ring 24 and a cylindrical portion 27h terminating in a thickened end 27C tting in the annular space between extension 19a and sleeve 26. Also placed within this annular space is a rubber ring seal 28 having a groove 28a mating with the tip of the thickened end 27C. End plate 19 is also provided with a plurality of openings 19t: circularly distributed about the axis of director 22 and through which screws 29 pass and thread through tapped holes 26a to contact a metallic ring 31 for exerting a force on s'eal 281 When screws 29 are tightcned, rubber ring 28isspread by the" tip of thickened end 27e and sealing is insured at this point, for reasons explained further below. End plate 19 is also provided with a plurali-ty of openingsl 159i: for passage therethrough of threaded bolts 32 and threaded caps 32a. When the position of element 27is` set by adjusting c'aps 3221 on threaded bolts 32, bolts 2'9' are tightened t'oV prevent movement of element 27 and insure proper sea-ling.

Also mounted withincasings 16am-l 17 is a deceleratin'g tube 33 having a divergent rear portion 33a and supported at one end by an annularv ring 34 and by three' ribs 35 at its other end. A flared sleeve 30E of case hardened metal to withstan'df the impact of the water and projectiles is secured rigidly tothe inlet end of tube 33 but is slidable with respect to ring 34. At the outlet endv oftube 33Y are mounted integrally therewithL thel three ribs 35l which are slidable with respect to casing 17. Thus, decelerating tube 33 withl flaredsleeve 30 at its' inlet is slidable with respect to casings 1`6 and' 17. One ofthe ribs 35'I is provided with two metal strips 17a axially arranged along tube 33 and attachedy to casing 17 for guiding the movement of tube 33 and preventing rotation. At the right endl of casing 17 is mounted rigid with tube a deflector 37 which is of heavy metallic materia-l, such as commercially available Kirksite. Deliector 37 with decelerating tu-be 33 is slidabl'e as a unit within casing 17, and is provided with a plate 4@ mounted in any conventional way, a r'od- 33 integral. therewith, and a stop 39, as better shown in Fig. 5. De'ilect'or 37 is made rigid with decelerating. tube 33 by the use of studs 45 passing thro-ugh plate 4) and deilector 37 to tube 33 where they are welded or attached in any other suitable manner. A slot 42 carved out of deector 37, best shown in Figs. 1 and 3, performs the actual function of reversing the water ow, while a high. ridge 43 in the center of slot 42 and trailing off at the edges thereof divides the water How so as to prevent excessive turbulence during reversal. Decelerating tube 33 and deflector' 37 are spring mounted within casing 17 by a spring 41 coiled about rod 38 for absorbing impact energy of the water and projectiles impinging against decelerating tube 33 and deflector 37. After reversal by deflector 37, the water then flows along the annular space surrounding tube 33, returning to tank 8 via conduit 13. A projectile trap assembly 44 in casing 17 separates out the projectiles, the shoulder at joint 18 functioning as a further obstacle to the movement of projectiles carried with the water.

The details of trap 44 are shown as a section in Fig. 3. Casing 17 is provided with a circular, transverse cutout 46 which in proper cross section, as shown in Fig. l, is circular. Into this section is placed a cylinder 47 which opens into the interior of casing 17. Within cylinder 17 is fitted a piston assembly 48 consisting of two pistons 49 and 51 connected at their bottoms by a semi-circular plate 55 fitting within the bottom of tube 47 and permitting movement of assembly 48 therein. Piston assembly 48 is provided with an extension 52 and a grip 53 for permitting the manual movement of the piston assembly 48. Cover 54 is screwed on the right end of tube 47 which is closed at its opposite end. When cover 54 is removed from tube 47 the piston assembly 48 may be partially withdrawn to empty the collected projectiles as hereinafter explained.

Operation of the hydrodynamic bullet catcher is as follows:

Pump 7 supplies water at a high pressure to chamber 10, and thence through annular orifice 23 expanding to atmospheric pressure forming a smooth convergent liow of water into chamber 15 facing llared sleeve 30, as shown in Fig. l. Seal 28 prevents the water under pressure in chamber from leaking out opening 21 which is exposed to the interior of director 22. Sleeve 30 is made of lia'rd material, such as a case hardened metal, because it must bear the brunt of heavy water impact.

The water enters tube 33 and flows therethrough solidly without entraining any air, as explained below. The solid flow of water passes, as illustrated by the arrows, to deflector 37 where it then passes in a reverse direction through the annular space between tube 33 and outer casings 16 and 17. The water and projectiles carried therewith pass over trap 44 into which the dissipated projectiles fall and collect. Shoulder 18a provided at 18 by the offset of casings 16 and 17 aids this process and prevents the projectiles from passing with the water into tank 8. Fig. 4 illustrates graphically how the bullet catcher destabilizes the approaching projectiles and per- -mits the rounds lired in rapid succession to be absorbed in a relatively short distance. lt will be noted that the water flowing through orifice 23, indicated by arrows, forms a cone which provides a solid water surface into which projectile 25 illustrated passes. The projectile, as is well understood in the art, is not only moving at a high rate of speed but is also rotating on its central axis so that the bullet is highly stable in motion. The bullet approaches the water surface of the cone and hits the surface at an angle from the projectile axis. The water presents a solid front and is highly resistant to its high speed movement. Because it would be a rare occurrence for the round to strike the cone exactly at its apex, the water front tends to deiiect the round from its line of motion. The water cone has a tremendous impact on the round and also interferes with its rotation. This effectively destabilizes the previously stable projectile which encounters further resistance through the column of water. It has been found that a solid column of moving water is far more effective in bringing the projectile to a stop ini a given distance than water having air entrapped therein; The arrangement, as illustrated, actually prevents air from being entrapped within tube 33 because of the conical water surface shown in Fig. 5. For example, the inside of the water cone from which the projectile approaches is open to` atmosphere through opening 21. At the apex of the cone the water llowing from orice 23 converges and a squeezing action at this point prevents air from being entrained therein, as tests have demonstrated'. Within chamber 15, surrounding the water cone, air is likewise not entrained in tube 33 because of the outer ared end of sleeve 30. Any water which actually does entrain some air is sheared olf by the edge of` sleeve 30 draining out through conduit 12. Thus, the water cone formed in chamber 15 performsat least two definite functions, as-described above.

Projectile trap 44 is designed large enough to hold the large number' of projectiles which may be lired in one test, totalling possibly several' hundred rounds. Between rings ofthe gun,7 While. the water is circulating through the system, cover 54 is removed from tube 47 enclosing piston assembly 48 having theV rounds trapped within, and is moved to dump the trapped rounds. Piston 51 remains within tube 47 and prevents the water inthe system from leaking out through tube 47 while this action is taken..

In operation, it is seen that pump 7 maintains a solid column of water within decelerating tube 33 of bullet catcher assembly 9.v Projectiles are firedl singly or in bursts from the gun 6. These: projectiles become entrained in the column of water within tube 53 where they are slowed to substantially the rate of flow of water and are tumbling by the time they reach dellector 37 which suifers only negligible damage. The water and the entrained projectiles are reversed in directionA by deector 37 which in so-doing effectively acts as a shock absorber for the whole column of water. This reverse flow also returns the water to tank 8 for reuse. Meanwhile, the projectiles, due to their weight, fall into trap 44.

This invention has several advantages over the conventional bank of sand and other hydrodynamic bulleti catchers described above. It is more compact. and fully enclosed.. Itis cleaner tov operateand: more economical since it` continuously recyclesthe water contained` inthe the force and frequency with which the latter strike the` wall of tube 33.

Many variations in structural detail are possible without deviating from the basic invention described herein. However, it is essential to maintain a solid column of water to receive the projectiles.

Various modifications as contemplated may obviously be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter defined by the appended claims, as only a preferred embodiment thereof has been disclosed.

What is claimed is:

1. A trap for high speed projectiles including a straight, elongated tubular member having an inlet for said projectiles and water, means for maintaining a moving solid column of water in said member, and means for maintaining a solid conical surface of water adjacent said inlet facing and impeding said high speed projectiles enn tering said tubular member.

2. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for water under pressure and rapidly moving projectiles, a tubular member within and spaced from the outer Wall of said unit having a forward end directed to receive said water and projectiles and having a rearwardly directed end for discharging said water and projectiles, and means for maintaining a moving solid column of water within said tubular member and a conical water surface at the inlet thereof for deflecting and destabilizing projectiles entering said tubular member.

3. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for water under pressure and rapidly moving projectiles, a tubular member within said unit having a forward end directed to receive said water and projectiles and having a rearwardly directed divergent end for discharging said water and projectiles, means for maintaining a moving solid column of water in said tubular member, and means for separating said projectiles from said Water after discharge from said tubular member.

4. The assembly of claim 3 wherein said means for maintaining a solid column of water in said tubular member includes orifice means for supplying a convergent ow of water to said tubular member and forming an inside conical water surface having the apex thereof adjacent the inlet of said tubular member.

5. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member within and spaced from said unit having a forward end directed to receive said liquid and projectiles, and having a rearwardly directed end for discharging said liquid and projectiles, means for maintaining a moving column of said liquid in said tubular member, and means adjacent said rearwardly directed end of said tubular member for reversing the ow of said liquid and projectiles back through the space between said tubular member and said elongated unit.

6. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member within said unit having a forward end directed to receive said liquid and projectiles and having a rearwardly directed end for discharging said liquid and projectiles, said member having a rear divergent portion for slowing down flow of said liquid and projectiles, means for maintaining a moving column of said liquid in said tubular member, and means adjacent said rearwardly directed end of said tubular member for reversing and absorbing the kinetic energy of said flow of said liquid and projectiles.

7. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member Within and spaced from said unit having a forward end directed to receive said liquid and projectiles, and having a rearwardly directed end for discharging said liquid and projectiles, and means for maintaining a solid internal conical surface of said liquid, the open end of said conical surface facing said projectiles and located between said projectile inlet and said forward end of said tubular member.

8. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member within and spaced from said unit having a forward end directed to receive said liquid and projectiles, and having a rearwardly directed end for discharging said liquid and projectiles, means for maintaining a solid internal conical surface of said liquid, the open end of said conical surface facing said projectiles and located between said projectile inlet and. said forward end of said tubular member, and means adjacent said rearwardly directed end of said tubular member for reversing the ow of said liquid and projectiles back through the space between said tubular member and said elongated unit.

9. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member within and spaced from said unit having a forward end directed to receive the liquid and projectiles and having a rearwardly directed end for discharging said liquid and projectiles, means for maintaining a moving column of said liquid in said tubular member, means adjacent said rearwardly directed end of said tubular member for reversing the llow of said liquid and projectiles back through the space between said tubular member and said elongated unit, and means for resiliently supporting said tubular member for limited axial movement with respect to said elongated unit for absorbing the energy of reversal of said moving column of liquid.

10. A bullet catcher assembly consisting of an elongated unit having at its forward end thereof separate inlets for a liquid under pressure and rapidly moving projectiles, a tubular member within and spaced from said unit having a forward end directed to receive said liquid and projectiles, and having a rearwardly directed end for discharging said liquid and projectiles, and means for maintaining a moving solid column of said liquid in said. member and a solid internal conical surface of said liquid, the open end of said conical surface facing said projectiles and located between said projectile inlet and said forward end of said tubular member.

References Cited in the tile of this patent UNITED STATES PATENTS 2,356,992 Gilson Aug. 29, 1944 2,518,445 Benson Aug. 15, 1950 2,518,446 Benson Aug. 15, 1950 

